A recently quenched galaxy 700 million years after the Big Bang

This paper reports the discovery of a mini-quenched galaxy at redshift z = 7.3, only 700 million years after the Big Bang. The galaxy, observed using JWST/NIRSpec, exhibits a blue UV color but shows a Balmer break and lacks nebular emission lines, indicating a recent cessation of star formation. Its stellar mass (4–6 × 10⁹ M⊙) is within a range sensitive to various feedback mechanisms, suggesting the quenching might be temporary.

Tobias J. Looser, Francesco D'Eugenio, Roberto Maiolino, Joris Witstok, Lester Sandles, Emma Curtis-Lake, Jacopo Chevallard, Sandro Tacchella, Benjamin D. Johnson, William M. Baker, Katherine A. Suess, Stefano Carniani, Pierre Ferruit, Santiago Arribas, Nina Bonaventura, Andrew J. Bunker, Alex J. Cameron, Stephane Charlot, Mirko Curti, Anna de Graaff, Michael V. Maseda, Tim Rawle, Hans-Walter Rix, Bruno Rodríguez Del Pino, Renske Smit, Hannah Übler, Chris Willott, Stacey Alberts, Eiichi Egami, Daniel J. Eisenstein, Ryan Endsley, Ryan Hausen, Marcia Rieke, Brant Robertson, Irene Shivaei, Christina C. Williams, Kristan Boyett, Zuyi Chen, Zhiyuan Ji, Gareth C. Jones, Nimisha Kumari, Erica Nelson, Michele Perna, Aayush Saxena, Jan Scholtz